core 自定义异常处理中间件

Intro

请求取消

请求取消导致的异常：

[HttpGet]
public async Task<IActionResult> GetAsync(string keyword, int pageNumber = 1, int pageSize = 10)
{
    Expression<Func<Notice, bool>> predict = n => true;
    if (!string.IsNullOrWhiteSpace(keyword))
    {
        predict = predict.And(n => n.NoticeTitle.Contains(keyword));
    }
    var result = await _repository.GetPagedListResultAsync(x => new
    {
        x.NoticeTitle,
        x.NoticeVisitCount,
        x.NoticeCustomPath,
        x.NoticePublisher,
        x.NoticePublishTime,
        x.NoticeImagePath
    }, queryBuilder => queryBuilder
            .WithPredict(predict)
            .WithOrderBy(q => q.OrderByDescending(_ => _.NoticePublishTime))
        , pageNumber, pageSize, HttpContext.RequestAborted); // 直接使用 HttpContext.RequestAborted

    return Ok(result);
}

// 在 Action 方法中声明  core 会自动将 `HttpContext.RequestAborted` 绑定到 CancellationToken 对象
[HttpGet]
public async Task<IActionResult> GetAsync(CancellationToken cancellationToken)
{
    var result = await _repository.GetResultAsync(p => new
    {
        p.PlaceName,
        p.PlaceIndex,
        p.PlaceId,
        p.MaxReservationPeriodNum
    }, builder => builder
    .WithPredict(x => x.IsActive)
    .WithOrderBy(x => x.OrderBy(_ => _.PlaceIndex).ThenBy(_ => _.UpdateTime)), cancellationToken);
    return Ok(result);
}

异常处理中间件

异常处理中间件源码：

public class CustomExceptionHandlerMiddleware
{
    private readonly RequestDelegate _next;
    private readonly CustomExceptionHandlerOptions _options;

    public CustomExceptionHandlerMiddleware(RequestDelegate next, IOptions<CustomExceptionHandlerOptions> options)
    {
        _next = next;
        _options = options.Value;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        try
        {
            await _next(context);
        }
        catch (System.Exception ex)
        {
            var logger = context.RequestServices.GetRequiredService<ILoggerFactory>()
                .CreateLogger<CustomExceptionHandlerMiddleware>();
            if (context.RequestAborted.IsCancellationRequested && (ex is TaskCanceledException || ex is OperationCanceledException))
            {
                _options.OnRequestAborted?.Invoke(context, logger);
            }
            else
            {
                _options.OnException?.Invoke(context, logger, ex);
            }
        }
    }
}

public class CustomExceptionHandlerOptions
{
    public Func<HttpContext, ILogger, Exception, Task> OnException { get; set; } =
        async (context, logger, exception) => logger.LogError(exception, $"Request exception, requestId: {context.TraceIdentifier}");

    public Func<HttpContext, ILogger, Task> OnRequestAborted { get; set; } =
        async (context, logger) => logger.LogInformation($"Request aborted, requestId: {context.TraceIdentifier}");
}

可以通过配置 CustomExceptionHandlerOptions 来实现自定义的异常处理逻辑，默认请求取消会记录一条 Information 级别的日志，其他异常则会记录一条 Error 级别的错误日志

你可以通过下面的示例来配置遇到请求取消异常的时候什么都不做

service.Configure(options=>
{
    options.OnRequestAborted = (context, logger) => 
});

Reference